Methods for enhancing plant growth using diacyl ureas

ABSTRACT

The present invention is directed to new compositions of matter comprising the reaction products of a carboxylic acid and a urea having the formula  
                 
 
     where R 1 , R 2 , R 3  and R 4  are the same or different and are selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, allyl, vinyl and alkoxyl groups having from 1-6 carbon atoms, substituted and unsubstituted phenyl groups and the halides. Preferably, the reaction product of the present invention is N,N′-diformylurea or N,N′-diacetylurea. These reaction products, e.g., diformylurea, have been found to produce significantly improved growth in a variety of agricultural products when applied to the seed, to the surrounding soil or to the foliage of the emerging plant. Because of the similarity in the carbon, nitrogen, oxygen structure of these reaction products with many biological compounds, it is believed that the reaction products of the present invention may find use in a variety of biological applications.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to new substituted ureas,to methods for preparing those substituted ureas and to agriculturaluses of those substituted ureas to improve plant growth. Morespecifically, the present invention is directed to the reaction productformed by reacting a carboxylic acid with urea to form a newN,N′-di-substituted urea, to methods for conducting that reaction and toagricultural uses of the reaction product.

[0003] 2. Description of the Background

[0004] Urea, being approximately 46% by weight nitrogen, has long beenpreferred as a nitrogen source for fertilizing soils to stimulate plantgrowth. However, urea suffers from high ammonia losses when used in thepresence of moisture. This disadvantage effectively restricted the useof urea for many years. It is believed that these losses are caused bythe hydrolysis of urea in the presence of moisture and the enzymeurease. The addition of a water soluble salt to aqueous solutions ofurea has been suggested as a means for reducing ammonia volatilization.See U.S. Pat. No. 4,500,335. While substituted ureas are also known,e.g., diphenylurea, they have found little agricultural use.

[0005] Urea undergoes condensation reactions with carboxylic acids toproduce barbituates and their analogs. These products have found noagricultural uses. However, the argicutural industry has felt the needfor ways to improve early seedling vigor and to increase plant biomass,both resulting in improved yield. There has been a long felt butunfulfilled need in the industry for improved methods for achievingthese goals. The present invention solves those needs.

SUMMARY OF THE INVENTION

[0006] The present invention is directed to new compositions of mattercomprising the reaction product of a carboxylic acid and a urea,including mono- and di-substitued ureas. The reaction product of thepresent invention comprises an N,N′-di-substituted urea having theformula

[0007] where R₁, R₂, R₃ and R₄ are the same or different and areselected from the group consisting of hydrogen, substituted andunsubstituted alkyl, allyl, vinyl and alkoxyl groups having from one tosix carbon atoms, substituted and unsubstituted phenyl groups and thehalides.

[0008] In a preferred embodiment, the second reactant is unsubstitutedurea so that R₃ and R₄ in the reaction product are hydrogen. In a morepreferred embodiment, R₁ and R₂ are selected from the group consistingof hydrogen and alkyl groups having from one to three carbon atoms. Mostpreferably, formic acid is reacted with urea in a molar ratio of about2:1 to produce N,N′-diformylurea. While the reaction may be conducted atany temperature between about 10° C. and about 140° C., it is preferablyconducted within the range of about 15° C. to about 40° C. The reactionmay conveniently be conducted at room temperature. Preferably thereactants are stirred until the reaction mixture is clear. Crystals ofthe reaction product will form and may be separated from the reactionmixture.

[0009] The reaction products of the present invention, most preferablyN,N′-diformylurea has been found to produce enhanced growth in plantswhen used in a variety of ways. These reaction products, most preferablydiformylurea, produce enhanced growth when applied to seeds prior toplanting, when applied to the soil surrounding the plant at or afterplanting or when applied to the foliage of the plant, e.g., at the threeleaf stage of growth. An aqueous solution containing from about0.001-1.0 M of the reaction product may be applied to the surface ofseeds at a rate of about 15-750 ml. of solution per 100 lbs of seed. Ina convenient method, the solution may be applied to the surface of theseeds or the seeds may be soaked in such a solution for about 2-24hours, preferably for about 24 hours, prior to planting. Alternatively,such a solution may be applied to the soil surrounding the seed and/oremerging plant. When so applied, it is suggested that the solution beapplied at a rate of about 1-100 grams of diformylurea or other reactionproduct per acre. Still another alternative is the application of suchan aqueous solution to the foliage of the plant, preferably at the threeleaf growth stage, at a rate of about 1-100 grams of diformylurea orother reaction product per acre. When applied to the foliage, thoseskilled in the art may include a conventional vegetable oil andsurfactant in the solution to improve the retention of reaction producton the leaves so that it may be more readily absorbed by the plant.

[0010] The newly discovered reaction products of urea and carboxylicacids described herein, particularly N,N′-diformylurea, have producedsignificantly improved growth when applied to the seeds and foliage of avariety of agricultural products. Accordingly, it is believed that asignificant improvement in crop development may be obtained using thesenew products. These and other meritorious features and advantages of thepresent invention will be more fully appreciated from the followingdetailed description and claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011] The present invention provides methods for preparing and usingthe reaction products of a carboxylic acid and a urea comprising newcompositions of matter. It has been found that these reaction productsmay be easily prepared and that they may have significant agriculturaluses because of their perceived biological activity. In fact, it hasbeen found that these reaction products, specifically N,N′-diformylurea,enhance the growth of a variety of agricultural crops when applied tothe seeds, surrounding soil or foliage.

[0012] The reaction products of the present invention have the generalformula

[0013] where R₁, R₂, R₃ and R₄ are the same or different and areselected from the group consisting of hydrogen, substituted andunsubstituted alkyl, allyl, vinyl and alkoxyl groups having from 1-6carbon atoms, substituted and unsubstituted phenyl groups and thehalides. These reaction products are prepared by reacting a carboxylicacid having the formula RCOOH where R is selected from the groupconsisting of hydrogen, substituted and unsubstituted alkyl, allyl,vinyl and alkoxyl groups having from 1-6 carbon atoms, substituted andunsubstituted phenyl groups and the halides. Exemplary acids includeformic acid, acetic acid, propionic acid, butyric acid, valeric acid,caproic acid, heptanoic acid, and citric acid. Preferably R is selectedfrom the group consisting of hydrogen and unsubstituted alkyl groupshaving from 1-3 carbon atoms. The presently most preferred acids areformic or acetic acid. These carboxylic acids are reacted with asubstituted or unsubstituted urea having the formula (NHR′)₂CO whereeach R′ is the same or different and is selected from the groupconsisting of hydrogen, substituted and unsubstituted alkyl groupshaving from 1-6 carbon atoms, substituted and unsubstituted alkoxylgroups having from 1-6 carbon atoms, substituted and unsubstitutedphenyl groups and the halides. Unsubstituted urea is the presently mostpreferred reactant.

[0014] In its most preferred embodiment, the present invention comprisesthe reaction product of urea and formic acid, i.e., N,N′-diformylurea,having the following formula

[0015] It has been found that the reaction of the present invention willproceed throughout a wide range of temperatures, e.g., from about 10° C.to about 140° C., restricted only by the boiling points of the reactantsand products. While heat may be added by any conventional means to speedthe rate of these reactions, it has been found that the methods of thepresent invention may conveniently be performed in a temperature rangefrom about 15° C. to about 40° C., preferably at room temperature, i.e.,from about 20° C. to about 30° C. These reactions appear to be slightlyexothermic. The reaction of formic acid and urea to form diformylureaproceeds to completion within 24 hours at room temperature. It ispreferred that the reaction mixture be stirred until clear and thenpermitted to remain quiescent until crystals of the reaction producthave formed.

[0016] It is believed that the reactions proceed by the elimination oftwo water molecules. The reaction of urea and formic acid proceeds asfollows:

H₂NCONH₂+2RCOOH→RCONHCONHCOR+2H₂O

[0017] In this reaction, formic acid reacts with one hydrogen on each ofthe urea nitrogens to produce N,N′-diformylurea. Accordingly, it ispreferred that the reaction mixture comprise about 2 moles of carboxylicacid for each mole of urea.

[0018] Applicant believes that these reaction products will bebiologically active as a result of the similarity of their skeletalstructure, i.e., the nitrogen-carbon-oxygen skeleton, with thealternating double bond structure of these same elements in a variety ofsynthetic and naturally occurring biological molecules. Thus, it isbelieved that these reaction products, e.g., N,N′-diformylurea, willfind a variety of biological uses. Applicant believes that thesecompounds may be used to produce, not only the improved plant growthshown herein, but that with the substitution of appropriate functionalgroups or bulky substituents, a variety of effective algaecides,herbicides, fungicides or pesticides may be produced.

[0019] Applicant believes that the reaction products claimed herein,particularly N,N′-diformylureas, may mimic plant growth hormones and/orplant growth regulators based upon the similarity of their skeletalstructure to a variety of biologically active compounds. Common to allbiologically active molecules in this class is a core structureincluding both alternating double bonds and alternating carbon tonitrogen bonds. These structures are common in all syntheticallyproduced and naturally occurring biologically active molecules, e.g.,cytokinens, substituted uracils, methylguanine and the like. Whileadenine and guanine have a fused ring structure, cytosine, thymine anduracil exhibit the same structures as pyrimidines. Because theN,N′-di-substituted ureas of the present invention, e.g., diformylurea,are linear, they can conform to the shapes of these biologicalmolecules. While this conformation is not exact, it is believed thatthis feature will facilitate the biological activity of these molecules.

[0020] The reaction products of the present invention, specificallyN,N′-diformylurea, have been used to enhance the growth of plants. Infact, it has been found that improved growth may be obtained by applyingdiformylurea to the seeds, or to the soil surrounding the plant, or tothe foliage of the plant. A single application of diformylurea has beenfound to produce significantly greater growth in a variety of crops,including wheat, corn, peanuts, soybeans, rice and cotton. For example,a single application to rice at the rate of 50 grams per acre attillering has produced a 25 percent increase in yield.

[0021] In one method of the present invention, seeds are treated with anaqueous solution containing the N,N′-di-substituted reaction product ofa carboxylic acid and urea. Seeds may conveniently be soaked in anaqueous solution of the reaction product for a time from about 2-24hours. Excellent results have been obtained with seeds soaked in anaqueous solution of diformylurea for about 24 hours. The seeds may beimmediately planted or may be dried to produce a seed which has beentreated with the reaction product.

[0022] While those skilled in the art will be able to prepare aqueoussolutions of the desired concentration for these agricultural uses, ithas been found that solutions containing from about 0.001-1.0 M of thereaction product are typically appropriate. Aqueous solutions containingfrom about 0.001-0.050 M are presently preferred. While these solutionsmay be applied at any rate desired by those of skill in the art, it hasbeen found that aqueous solutions of the foregoing concentration providegood results when applied at the rate of about 15-750 ml. per 100 lbs ofseed. Alternatively, it is believed that the reaction products of thepresent invention, typically in aqueous solutions of the foregoingconcentrations, may be added to the soil surrounding the seed atplanting or after emergence of the plant.

[0023] In another alternative method, excellent results have beenobtained by a one time spraying of the foliage of the emerging plant,preferably at the three leaf stage, with an aqueous solution containingthe reaction product. Those skilled in the art would be aware thataddition of a small quantity of oil and/or surfactant to the aqueoussolution sprayed on the foliage will improve the adherence of thereaction product to the leaves and the uptake of the reaction product bythe plant. Suitable oils include both saturated and unsaturated oils,alcohols, esters and other compounds having both hydrosphobic andhydrophilic functional groups. Exemplary oils comprise the vegetableoils and include sunflower oil and soybean oil. Exemplary biologicallyacceptable surfactants include the organic polyphosphates andethoxylated nonophenols. Again, those skilled in the art can determineappropriate concentrations for each desired use. However, aqueoussolutions having the foregoing concentrations are believed to begenerally appropriate. These solutions should be applied at a ratesufficient to provide about 1-100 grams of reaction product per acre.

[0024] The following are examples illustrating methods for preparingreaction products of the present invention, specificallyN,N′-diformylurea and N,N′-diacetylurea, and results of applyingdiformylurea to a variety of agricultural crops.

[0025] The Preparation of N,N′-Diformylurea

[0026] Diformylurea has been prepared by reacting formic acid with ureain a molar ratio of about 1.8-2.0 moles formic acid to 1.0 mole urea. Ina first example, 600 grams of urea was reacted with 920 grams of 90%formic acid. The molar ratio of formic acid to urea in this example isabout 1.8 to 1. In a second example, 555 grams of urea was reacted with945 grams of 90% formic acid. In this example, the molar ratio of formicacid to urea is about 2:1. The reaction mixture of both examples wasstirred about 1 hour until the solution was clear. The clear solutionwas allowed to stand for about 48 hours at room temperature. Within 24hours, substantially all of the reaction mixture had crystalized. Atabout 48 hours, the remaining liquid was decanted and the crystalspurified by rinsing with the mother liquor and ice water using vacuumfiltration. Upon analysis, only a single reaction product, i.e.,N,N′-diformylurea, was found. Unexpectedly the formic acid had reactedon both of the urea nitrogens.

[0027] Preparation of N,N′-Diacetylurea

[0028] Diacetylurea was prepared by reacting 219 grams of urea with 438grams of 99% acetic acid. The molar ratio of acetic acid to urea isabout 2:1. The reaction mixture was stirred for about 1 hour until clearas before. Upon standing, crystals of N,N′-diacetylurea formed. Thecrystals were purified as described above.

[0029] It is believed that the reaction of carboxylic acid and urea maybe accelerated by addition of a catalytic quantity of a transitionmetal, e.g., iron or zinc oxide or a complex of copper II and thereaction product of formic acid and urea described above.

[0030] Agricultural Use of N,N′-Diformylurea

[0031] In a preliminary experiment to determine the agricultural valueof the N,N′-diformylurea prepared above, a concentrate was prepared bymixing 200 grams diformylurea and 200 grams formic acid, adjusting theph to about 5.5 by the addition of potassium hydroxide and addingsufficient water to make 1 liter. This results in a concentrate having aconcentration of 1.7 M diformylurea and 4.3 M formate. Low, medium andhigh dilution aqueous solutions were prepared by diluting, respectively,0.8 grams, 8.0 grams and 40.0 grams of the concentrate per liter offinal solution. Thus, the concentration of diformylurea in the lowdilution was 0.0013 M. The concentration of diformylurea in the mediumdilution was 0.013 M., while the high concentration dilution had aconcentration of 0.068 M. diformylurea.

[0032] The foregoing solutions were used to coat corn, soybean, cottonand rice seeds prior to planting. Coating was achieved by soaking theseeds in the foregoing solutions for about 24 hours. Sufficient solutionwas used to keep the seeds immersed. Control seeds were soaked in waterfor the same time.

[0033] Untreated or control seeds, together with seeds treated by thelow, medium and high dilution solutions, were planted in 1 gallongreenhouse pots. Six pots were used for each dilution or control withfive seeds planted per pot. The plants were thinned to two plants perpot after emergence. The plants were watered and fertilized as required.After 30 days the plants were harvested and the roots and shootsexamined.

[0034] The roots and shoots were weighed separately and the root/shootratio determined. The treated plants were generally characterized byboth greater root mass and shoot mass when compared to the controls. Theroot/shoot ratio for most of the treated plants was greater than thatfor the controls. Further, the older leaves of plants grown from thetreated seeds appeared to exhibit greater length and width than thosefrom plants grown from the untreated seeds. Finally, crown roots werenoticed on both corn and rice plants grown from the treated seeds. Theresults of these preliminary tests are summarized in Table I. TABLE ISeed Treated Control Low Medium High Cotton Roots (gm) 3.03 7.85 4.505.07 Shoots (gm) 4.57 5.38 5.25 6.90 Total (gm) 7.60 13.23 9.75 11.97Root/Shoot Ratio 0.66 1.46 1.08 0.73 Rice Roots (gm) 0.47 0.61 3.07 0.82Shoots (gm) 0.24 0.34 1.84 0.39 Total (gm) 0.71 0.95 4.91 1.21Root/Shoot Ratio 1.95 1.78 1.86 2.10 Corn Roots (gm) 9.00 9.80 10.409.60 Shoots (gm) 9.60 9.40 9.60 8.80 Total (gm) 18.60 19.20 20.00 18.40Root/Shoot Ratio 0.94 1.04 1.08 1.09 Soybean Roots (gm) 2.40 4.60 4.90 —Shoots (gm) 3.80 4.90 4.10 — Total (gm) 6.20 9.50 9.00 — Root/ShootRatio 0.63 0.93 1.20 —

[0035] Table I illustrates the improved growth achieved by treatingseeds prior to planting with an aqueous solution containingdiformylurea. In substantially every example the treated seeds producedplants having greater root mass, greater shoot mass and greater totalmass. Further, the ratio of root to shoot mass was increased in all ofthe treated cotton, corn and soybean samples.

[0036] Based upon the foregoing preliminary work, additional experimentsto investigate the effect of diformylurea on other plant species wasundertaken. These experiments were also designed to compare the effectof treating seeds as described above with foliar treatment. Wheat, cornand peanuts were selected for the next phase of this work. Diformylureawas prepared by reacting formic acid and urea at a molar ratio of 2:1 asdescribed above. An aqueous solution containing diformylurea at aconcentration of 0.01 M was prepared. For the seed treatment portion ofthe experiments, the seeds to be treated were soaked in the foregoingsolution for about 24 hours before planting. The control seeds wereagain soaked in water for the same time. Both control and treated seedswere planted in 1 gallon greenhouse pots. Five seeds were planted ineach pot. Each pot was thinned to two plants after germination. For thefoliar treatment portion of the experiment, plants grown from untreatedseeds were sprayed with a solution containing 0.01 M. diformylurea atthe three leaf stage. All plants were watered and fertilized asrequired. Thirty days after planting, the plants were harvested and theroots and shoots examined. The mass of both the roots and shoots and thetotal mass of the plant in each pot were determined. The results forthese experiments for control, seed treated and foliar treated wheat,corn and peanuts are reported in Tables II-IV, respectively. TABLE IIWheat Seed Treated Foliar Treated Control 0.01 M diformylurea 0.01 Mdiformylurea Shoots Total Roots Shoots Total Roots Shoots Total SampleRoots (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) 1 12.10 1.41 13.5146.50 9.76 56.26 14.00 4.00 18.00 2 30.04 3.19 33.23 65.06 12.94 78.0026.81 7.28 34.09 3 29.63 5.15 34.78 27.98 4.17 32.15 37.26 7.48 44.74 414.98 2.03 17.01 41.69 12.22 53.91 25.13 7.53 32.66 5 59.01 15.66 74.6720.12 4.44 24.56 6 17.90 2.36 20.26 32.14 7.32 39.46 20.28 4.62 24.90average 20.93 2.83 23.76 45.40 10.35 55.74 23.93 5.89 29.83

[0037] TABLE III Corn Seed Treated Foliar Treated Control 0.01 Mdiformylurea 0.01 M diformylurea Shoots Total Roots Shoots Total RootsShoots Total Sample Roots (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) 155.31 43.19 98.50 57.78 46.12 103.90 42.18 67.57 109.75 2 50.53 26.1676.69 80.82 34.73 115.55 66.57 56.61 123.18 3 50.91 24.55 75.46 38.1517.33 55.48 42.40 61.80 104.20 4 30.95 29.65 60.60 57.78 46.12 103.9048.44 46.17 84.61 5 39.73 17.53 57.26 80.82 34.73 115.55 52.48 50.59103.07 6 45.49 28.22 73.71 38.15 17.33 55.48 56.22 61.12 117.34 average46.15 28.22 74.37 58.92 32.73 91.65 51.38 57.31 108.69

[0038] TABLE IV Peanuts Seed Treated Foliar Treated Control 0.01 Mdiformylurea 0.01 M diformylurea Shoots Total Roots Shoots Total RootsShoots Total Sample Roots (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) 118.46 14.66 33.12 16.46 20.20 36.66 31.69 36.17 67.86 2 17.29 10.8628.15 22.65 22.00 44.65 33.55 31.82 65.37 3 15.96 10.60 26.56 20.1120.46 40.57 27.67 28.38 56.05 4 13.19 14.77 27.96 22.04 22.34 44.3835.04 30.34 65.38 5 19.52 17.85 37.37 21.60 19.03 40.63 37.38 33.8471.22 6 17.92 23.90 41.82 16.74 17.77 34.51 31.10 32.35 63.45 average17.06 15.44 32.50 19.93 20.30 40.23 32.74 32.15 64.89

[0039] A review of Tables II-IV establishes that the root mass, shootmass and total plant mass appear to be increased in response to bothtreatment of the seeds and foliar treatment of the emerging leaves withan aqueous solution of diformylurea for each of the three tested crops.Average weights for the plants grown from untreated, seed treated andfoliar treated seeds for each crop are reported in Table V. TABLE VWheat Corn Peanuts Seed Foliar Seed Foliar Seed Foliar Control TreatedTreated Control Treated Treated Control Treated Treated Roots (gm) 20.9345.40 23.93 46.15 58.92 51.38 17.06 19.93 32.74 Shoots (gm) 2.83 10.355.89 28.22 32.73 57.31 15.44 20.30 32.15 Total (gm) 23.76 55.74 29.8374.37 91.65 108.69 32.50 40.23 64.89 Root/Shoot 7.40 4.39 4.06 1.61 1.800.90 1.10 0.98 1.02 Ratio Percent Roots 117 14 30 11 17 92 Change V.Shoots 266 108 16 103 31 108 Control Total 135 26 24 46 24 100

[0040] The observed average weights for the roots, shoots and totalmass, together with the percentage change versus control, for each ofthe three crops for both seed and foliar treatment are listed in TableV. Root mass, shoot mass and total mass increased for each of thesethree crops when treated with diformylurea, whether seed or foliarapplied. The mass of the seed treated wheat was 135% greater than thecontrol while that of the foliar treated peanuts was 100% greater. Theremaining total mass results showed increases of 24-46% with respect tothe control. The root to shoot ratios in these experiments were mixed.It appears that increased plant mass, both root and shoot, will beachieved by application of diformylurea to the seeds prior to plantingor to the foliage after emergence.

[0041] Additional experiments were designed to study further the effectof the concentration of diformylurea applied to the seeds of severalother crops. These experiments were conducted using cotton, rice, cornand soybeans. These experiments were similar to the preliminaryexperiments described above. The concentrate described above, containingboth diformylurea and formate, was used to prepare solutions containinglow, medium and high concentrations of diformylurea having,respectively, 0.001 M, 0.01 M and 0.05 M diformylurea. These solutionswere used to treat the seeds of cotton, rice, corn and soybeans. Seedsof each of these crops were soaked in water or the prepared aqueoussolutions of diformylurea for 24 hours before planting. Five seeds wereplanted in each of six, 1 gallon greenhouse pots. Pots were thinned totwo plants after germination and the plants watered and fertilized asneeded for 30 days. Thereafter, the plants were harvested and the massof the roots, shoots and total mass determined. Those results, togetherwith the averages are reported in Tables VI-IX. TABLE VI Cotton SeedTreated Seed Treated Seed Treated Control 0.001 M diformylurea 0.01 Mdiformylurea 0.05 M diformylurea Roots Shoots Total Roots Shoots TotalRoots Shoots Total Roots Shoots Total Sample (gm) (gm) (gm) (gm) (gm)(gm) (gm) (gm) (gm) (gm) (gm) (gm) 1 4.70 4.80 9.50 6.90 5.70 12.60 6.904.80 11.70 4.70 6.90 11.60 2 1.50 4.50 6.00 9.20 5.70 14.90 2.40 4.607.00 6.60 7.00 13.60 3 2.90 4.40 7.30 3.80 4.80 8.60 1.90 4.00 5.90 4.304.70 9.00 4 8.00 4.40 12.40 4.20 6.00 10.20 6.00 5.00 11.00 5 10.00 6.2016.20 7.60 4.90 12.50 4.20 6.40 10.60 6 9.20 5.50 14.70 4.00 7.20 11.204.60 5.40 10.80 Average 3.03 4.57 7.60 7.85 5.38 13.23 4.50 5.25 9.755.07 5.90 10.97

[0042] TABLE VII Rice Seed Treated Seed Treated Seed Treated Control0.001 M diformylurea 0.01 M diformylurea 0.05 M diformylurea RootsShoots Total Roots Shoots Total Roots Shoots Total Roots Shoots TotalSample (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) 10.58 0.26 0.85 0.93 0.46 1.39 0.40 0.23 0.63 0.38 0.30 0.68 2 0.34 0.170.51 0.59 0.34 0.93 0.78 0.40 1.18 0.94 0.33 1.27 3 0.42 0.29 0.71 0.200.13 0.33 0.52 0.26 0.78 1.19 0.46 1.65 4 0.55 0.37 0.92 0.27 0.13 0.400.21 0.18 0.39 5 1.11 0.52 1.62 0.45 0.38 0.83 0.78 0.41 1.19 6 0.280.23 0.51 0.65 0.44 1.09 1.43 0.63 2.06 Average 0.45 0.24 0.69 0.61 0.340.95 0.51 0.31 0.82 0.82 0.39 1.21

[0043] TABLE IX Soybean Seed Treated Seed Treated Control 0.01 Mdiformylurea 0.01 M diformylurea Shoots Total Roots Shoots Total RootsShoots Total Sample Roots (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) (gm) 15.10 7.90 13.00 7.80 8.70 16.50 12.40 9.90 22.30 2 4.50 6.90 11.40 8.409.80 18.20 5.70 8.90 14.60 3 5.00 8.10 13.10 7.30 10.20 17.50 8.40 11.2019.60 4 8.00 10.30 18.30 5.00 6.00 11.00 5 11.30 9.30 20.60 5.90 8.3014.20 6 12.30 10.90 23.20 Average 4.87 7.63 12.50 9.18 9.87 19.05 7.488.86 16.34

[0044] Review of the data reported in the foregoing tables illustratesthat cotton, rice, corn and soybean seeds treated with an aqueoussolution of diformylurea consistently produced plants having increasedroot, shoot and total plant mass. These improved results were obtainedover a wide concentration range from at least about 0.001M diformylureato at least about 0.05 M diformylurea in the aqueous solution in whichthe seeds were soaked. Table X illustrates the percentage change withrespect to control for the root, shoot and total plant mass in theseexperiments. TABLE X Root/Shoot Percent Change v. Control Ratio RootsShoots Total Cotton Control 0.66 — — — 0.001 M diformylurea 1.46 159 1874  0.01 M diformylurea 0.86 49 15 28  0.05 M diformylurea 0.86 67 29 44Rice Control 1.86 — — — 0.001 M diformylurea 1.79 37 42 39  0.01 Mdiformylurea 1.67 13 29 19  0.05 M diformylurea 2.13 82 63 76 CornControl 1.07 — — — 0.001 M diformylurea 1.04 2 5 3  0.01 M diformylurea1.09 9 7 8  0.05 M diformylurea 1.09 0 −2 −1 Soybean Control 0.64 — — —0.001 M diformylurea 0.93 89 29 52  0.01 M diformylurea 0.84 54 16 31

[0045] In substantially every case, both root and shoot mass increasedfor plants emerging from seeds treated with diformylurea. The root toshoot ratio for these plants is also illustrated in Table X. The ratioincreased for both cotton and soybean and remained generally the samefor rice and corn.

[0046] The foregoing description of the invention has been directed inprimary part to particularly preferred embodiments in accord with therequirements of the Patent Statute and for purposes of explanation andillustration. It will be apparent, however, to those skilled in the artthat many modifications and changes in the specifically described systemmay be made without departing from the true scope and spirit of theinvention. For example, while most of the work reported herein employsdiformylurea, other N,N′-di-substituted ureas comprising the reactionproduct of carboxylic acids and urea may also be found to provideimproved results. Further, those skilled in the art will be aware thatthe concentration of reaction product in aqueous solution may beadjusted as required based upon the nature of each crop or theapplication equipment. Therefore, the invention is not restricted to thepreferred embodiments described and illustrated but covers allmodifications which may fall within the scope of the following claims.

What is claimed is:
 1. A composition of matter comprising diformylureahaving the formula


2. A composition of matter having the formula

where R₁, R₂, R₃ and R₄, are the same or different and are selected fromthe group consisting of hydrogen, substituted and unsubstituted alkyl,allyl, vinyl and alkoxyl groups having from 1 to 6 carbon atoms,substituted and unsubstituted phenyl groups and the halides.
 3. Thecomposition of matter of claim 2 wherein R₃ and R₄ are hydrogen.
 4. Thecomposition of matter of claim 3 wherein R₁ and R₂ are selected from thegroup consisting of hydrogen and alkyl groups having from 1 to 3 carbonatoms.
 5. The composition of matter of claim 3 wherein R₁ and R₂ aremethyl.
 6. A reaction product formed by reacting formic acid with ureawhere the molar ratio of formic acid to urea is about 2:1.
 7. A reactionproduct formed by reacting a carboxylic acid having from 1 to 7 carbonatoms with urea where the molar ratio of carboxylic acid to urea isabout 2:1.
 8. The reaction product of claim 7 wherein said carboxylicacid is acetic acid.
 9. The reaction product of claim 7 wherein saidcarboxylic acid has the formula RCOOH where R is selected from the groupconsisting of hydrogen, substituted and unsubstituted alkyl, allyl,vinyl and alkoxyl groups having from 1 to 6 carbon atoms, substitutedand unsubstituted phenyl groups and the halides.
 10. The reactionproduct of claim 9 wherein said urea has the formula (NHR′)₂CO whereeach R′ is the same or different and is selected from the groupconsisting of hydrogen, substituted and unsubstituted alkyl groupshaving from 1 to 6 carbon atoms, substituted and unsubstituted alkoxylgroups having from 1 to 6 carbon atoms, substituted and unsubstitutedphenyl groups and the halides.
 11. A method for preparing diformylureahaving the formula

comprising reacting formic acid with urea.
 12. A method for preparing asubstituted urea having the formula

comprising reacting a carboxylic acid with a reactant selected from thegroup consisting of urea, N-mono-substituted ureas andN,N′-di-substituted ureas, where R₁, R₂, R₃ and R₄, are the same ordifferent and are selected from the group consisting of hydrogen,substituted and unsubstituted alkyl, allyl, vinyl and alkoxyl groupshaving from 1 to 6 carbon atoms, substituted and unsubstituted phenylgroups and the halides.
 13. The method of claim 12 wherein the molarratio of carboxylic acid to urea is about 2:1.
 19. A method forenhancing the growth of a plant, comprising applying to seeds for saidplant prior to planting, to soil surrounding said plant, or to foliageof said plant, an N,N′-substituted urea having the formula

where R₁, R₂, R₃ and R₄ are the same or different and are selected fromthe group consisting of hydrogen, substituted and unsubstituted alkyl,allyl, vinyl and alkoxyl groups having from 1 to 6 carbon atoms,substituted and unsubstituted phenyl groups and the halides.
 20. Themethod of claim 19 wherein R₁, R₂, R₃ and R₄ are hydrogen.
 21. Themethod of claim 19 wherein an aqueous solution having a concentrationfrom about 0.001-1.0 M of said N,N′-substituted urea is applied to saidseeds at a rate of about 15-750 ml. of solution per 100 lbs. of seed.22. The method of claim 21 wherein R₁, R₂, R₃ and R₄ are hydrogen. 23.The method of claim 21 wherein said seeds are soaked in said solutionfor about 2-48 hours prior to planting.
 24. The method of claim 19wherein an aqueous solution having a concentration from about 0.0001-1.0M of said N.N′-substituted urea is applied to said foliage at a rate ofabout 1-100 gm. of said substituted urea per acre.
 25. The method ofclaim 24 wherein R₁, R₂, R₃ and R₄ are hydrogen.
 26. The method of claim24 wherein said solution further comprises a vegetable oil and asurfactant.
 27. The method of claim 26 wherein said vegetable oil isselected from the group consisting of, sunflower oil and soybean oil,and said surfactant is related from the group consisting of organicpolyphosphates and ethoxylated nonophenols.
 28. A method for enhancingthe growth of a plant, comprising applying to seeds for said plant priorto planting, to soil surrounding said plant or to foliage of said plantan N,N′-substituted urea selected from the group consisting of thecompositions of matter of claims 1-5 and the reaction products of claims6-10.
 29. A treated seed comprising a plant seed to which has beenapplied an N,N′-substituted urea having the formula

where R₁, R₂, R₃ and R₄ are the same or different and are selected fromthe group consisting of hydrogen, substituted and unsubstituted alkyl,allyl, vinyl and alkoxyl groups having from 1 to 6 carbon atoms,substituted and unsubstituted phenyl groups and the halides.
 30. Thetreated seed of claim 29 wherein R₁, R₂, R₃ and R₄ are hydrogen.
 31. Thetreated seed of claim 29 wherein said plant seed has been soaked in anaqueous solution containing said N,N′-substituted urea.
 32. An improvedplant seed comprising a seed to which has been applied anN,N′-substituted urea having the formula

where R₁, R₂, R₃ and R₄ are the same or different and are selected fromthe group consisting of hydrogen, substituted and unsubstituted alkyl,allyl, vinyl and alkoxyl groups having from 1 to 6 carbon atoms,substituted and unsubstituted phenyl groups and the halides.
 33. Theimproved plant seed of claim 31 wherein R₁, R₂, R₃ and R₄ are hydrogen.